The present invention relates to locking devices for preventing the rotation and/or the axial movement of a pin, of the type including a coil spring wound around at least a portion of the pin. In devices of this type, the aforesaid spring has one end rigidly connected to a support structure. In the undeformed condition, the spring has an internal diameter lower than the diameter of the pin, whereby in its rest condition, it is tightened around the pin such as to prevent a rotation thereof at least in one direction and/or an axial movement in any direction. In case of devices of this type, means are further provided for causing unwinding of the turns of the spring, for the purpose of temporarily releasing the device, enabling a rotation and/or an axial movement of the pin.
A device of the above indicated type is described, for example, in GB-A-2 078 846.